Modern televisions and other electronic devices receive video signals that typically must be digitized before being processed. These analog video signals come in various formats. Composite video signals, for example, contain chrominance (hue and saturation) and luminance (brightness) information, along with synchronization and blanking pulses, all together in a single signal. Component video signals contain a number of distinct signals, each carrying a component of the total video information. Examples of component video signals are red, green, and blue (RGB) signals where each signal represents one of the primary colors. Another example of component video signals are luminance signal Y and color difference signals PB and PR, where each signal is a linear combination of signals representing the three primary colors. Yet another example is S-video, sometimes referred to as Y/C video, in which the luminance signal Y and the chrominance signal C are transmitted separately to achieve superior picture clarity. The luminance signal Y carries brightness information that defines the black and white portion, and the chrominance signal C carries color information that defines hue and saturation.
FIG. 1 is a block diagram of a typical digitization system 10. Referring to FIG. 1, the digitization system 10 includes channels 11, 12, and 13 to receive a plurality of video signals, e.g., R, G, and B signals respectively. Or channels 11, 12, and 13 may receive PR, Y, PB signals respectively. The digitization system 10 uses one analog-to-digital converter (ADC) per channel, three ADCs 21, 22, and 23 to receive the R, G, and B signals on corresponding channels. Three ADCs 21, 22, and 23 are typically required to digitize the PR, Y, and PB signals comprising a component video signal. Two ADCs 22 and 23 are required to digitize S-video signals, one for each of the luminance Y and chrominance C signals.
Digitization systems with multiple ADCs, like system 10, require large silicon die areas making them expensive to design, test, and manufacture. And digitization systems with multiple ADCs, like system 10, consume large power amounts.
Accordingly, a need remains for an improved video digitization system and method.